My motor makes a little noise when cold which gets reduced somewhat when warm. I put a timing light on the engine and it occurs at roughly the same frequency as the spark so I'm guessing it's not the bottom end.

I had put in new valve stem seals but didn't wiggle the valves to check for clearance in the guide becaue I was afraid of loosing the air pressure and dropping the valve. My plugs where burning clean for a while but now after 600 miles it looks like they are starting to foul a little, not on the insulator but on the outer ring. This morning it puffed blue at start up, first time ever.
The noise sounds almost like a lifter but it has a duller sound, more like a "klock" than a "click" for lack of a better description. It's also not as metalic or clattery as what I've been told was piston slap in other motors.The motor has about 110k miles on it, makes good oil pressure, and is running 15w-50 Mobil with I'd guess a quart/3000miles consumption.

Any guesses or hints on how to diagnose? I'd almost say it's a rocker but haven't heard one of those before.

Jorg